Federico Caselli

Hsp70 expression in thermally stressed Ostrea edulis, a commercially important oyster in Europe

Abstract Synthesis of heat shock proteins (Hsps) in response to elevated temperatures and other denaturing agents is a common feature of prokaryotic and eukaryotic cells. The heat-induced expression of Hsp70 family members in the gills and mantle of Ostrea edulis, a highly valued fisheries resource inhabiting primarily estuarine environments, has been studied. O edulis is exposed to a variety of natural and anthropogenic stresses in the environment. Two isoforms of about 72 kDa and 77 kDa were constitutively present in unstressed organisms, reflecting the housekeeping function performed by these proteins under normal circumstances. Their expression in animals undergoing thermal stress was highly variable, and on the average, little change occurred under different experimental conditions. A third isoform of about 69 kDa was induced in both tissues after exposure to ≥32°C; its synthesis was detected within 4 hours of poststress recovery at 15°C, reaching the maximum expression after 24 hours in the gills and after 48 hours in the mantle and declining thereafter. Hsp69 expression was low at 38°C, a temperature lethal for about 50% of the individuals tested. Densitometric analysis of Western blots revealed that Hsp69 was mostly responsible for the significant heat-induced overexpression of Hsp70s in O edulis. Comparison with heat shock responses in tissues of Crassostrea gigas indicated a similar pattern of Hsp70 expression. In this organism, however, Hsp69 was induced after exposure to ≥38°C. We conclude that tissue expression of Hsp69 in O edulis, and possibly other bivalves, is an early sign of thermal stress; determining whether these changes also correlate with other major environmental stresses is the goal of ongoing studies.

Cd2+ and Hg2+ affect glucose release and cAMP-dependent transduction pathway in isolated eel hepatocytes.

Isolated hepatocytes of the European eel (Anguilla anguilla) have been used as experimental model to characterize the effects of Cd(2+) and Hg(2+) on either basal or epinephrine-stimulated glucose release. Cd(2+) strongly reduced glucose output from cells perifused in BioGel P4 columns and challenged with epinephrine, with a maximum inhibition of 95% reached at 10 microM (IC(50) 0.04 microM). The epinephrine-stimulated glucose output was also reduced by Hg(2+), although a significant inhibition of about 60% was achieved only at 10 microM (IC(50) 5 microM). The possible influence of Cd(2+) and Hg(2+) on adenylyl cyclase/cAMP transduction pathway has been investigated, since this system is known to play a pivotal role in the regulation of fish liver glycogen breakdown and consequent glucose release. Micromolar concentrations of both heavy metals significantly reduced the epinephrine-modulated cAMP levels in isolated eel hepatocytes, in good agreement with the reduction of glucose output. Cd(2+) and Hg(2+) also significantly reduced basal and epinephrine-stimulated adenylyl cyclase activity in liver membrane preparations. A competitive inhibition with respect to Mg(2+) was shown by Cd(2+) and Hg(2+), which significantly reduced the affinity of the allosteric activator for the adenylyl cyclase system. Apparent Km for Mg(2+) was 4.35 mM in basal conditions, and increased to 9.1 and 7.1 mM in the presence of 10 microM Cd(2+) and Hg(2+), respectively. These results indicate that Cd(2+) and Hg(2+) may impair a crucial intracellular transduction pathway involved in the adrenergic control of glucose metabolism, but also in several other routes of hormonal regulation of liver functions.

Use of Mytilus galloprovincialis and Tapes philippinarum as sentinel organisms for the development of a biosurveillance program in the Pialassa Baiona coastal lagoon (Ravenna, Italy)

The Pialassa Baiona is an intertidal lagoon located north from the town of Ravenna (Italy). It shows a certain degree of contamination caused by past uncontrolled discharges, and we aim at developing a bioassessment program to be used for future monitoring and conservation plans. A battery of six biomarkers (lysosome membrane stability, lipofuscin and neutral lipid accumulation, hsp70 expression, metallothionein levels and acetylcholinesterase (AChE) activity) was investigated in Mytilus galloprovincialis transplanted for 30 days in different sites. Tapes philippinarum are widely distributed within the lagoon, and we explored the possibility to use resident clams for future biosurveillance programs. Adenylyl cyclase (ACase) activity was also assessed in tissues of both bivalves as a future possible biomarker. Taken together, our results indicate that mussels are suitable sentinel organisms also within such a peculiar environment; alteration of four biomarkers was observed in tissues of mussels transplanted in two sites out of the five analyzed, indicating their low water quality. T. philippinarum showed a barely detectable AChE activity and absence of neutral lipids in digestive glands, therefore appeared unsuitable for our purpose, at least using the selected battery of biomarkers. ACase activity was not different among animals collected from the different sites.

Implementing and evaluating V2X protocols over iTETRIS: traffic estimation in the COLOMBO project

Improving the efficiency of urban vehicular mobility, also via the optimized management of the dynamic behavior of traffic lights with limited infrastructure investments and limited operational costs, is widely recognized as a crucial goal for smart cities, capable of relevant economic impacts in terms of travel time/cost reduction and better sustainability. Within this context, in the framework of the ongoing EU FP7 COLOMBO project, we are investigating, developing, and thoroughly evaluating innovative locality-based vehicular cooperation protocols for the determination of traffic characteristics in proximity of intersections, with no need for communication towards global data collection centers. One of the specific and original goals in COLOMBO is to achieve reasonable and sufficiently accurate traffic estimations with limited penetration rates of actively participating vehicles equipped with differentiated V2X capabilities (full-fledged V2X-enabled cars but also vehicles with only onboard smartphones). In this paper, we specifically focus on our recent research work of implementation and evaluation of our protocols on top of the iTETRIS simulation platform, a state-of-the-art integrated platform resulted from the synergic interworking of the ns-3 network and the SUMO vehicular mobility simulators. In particular, here we originally describe how to effectively and efficiently implement V2X protocols on iTETRIS, as well as lessons learned from our practical experience of deployment, evaluation, and protocol/iTETRIS fine-tuning. The reported simulation results (obtained through realistic simulations based on real traffic traces and the real road topology of the city of Bologna) show the feasibility of the proposed approach also with very limited penetration rates.

Swarm-Based Controller for Traffic Lights Management

This paper presents a Traffic Lights control system, inspired by Swarm intelligence methodologies, in which every intersection controller makes independent decisions to pursue common goals and is able to improve the global traffic performance. The solution is low cost and widely applicable to different urban scenarios. This work is developed within the COLOMBO european project. Control methods are divided into macroscopic and microscopic control levels: the former reacts to macroscopic key figures such as mean congestion length and mean traffic density and acts on the choice of the signal program or the development of the frame signal program; the latter includes changes at short notice based on changes in the traffic flow: they include methods for signal program adaptation and development. The developed system has been widely tested on synthetic benchmarks with promising results.

Cooperative Vehicular Traffic Monitoring in Realistic Low Penetration Scenarios: The COLOMBO Experience

The relevance of effective and efficient solutions for vehicle traffic surveillance is widely recognized in order to enable advanced strategies for traffic management, e.g., based on dynamically adaptive and decentralized traffic light management. However, most related solutions in the literature, based on the powerful enabler of cooperative vehicular communications, assume the complete penetration rate of connectivity/communication technologies (and willingness to participate in the collaborative surveillance service) over the targeted vehicle population, thus making them not applicable nowadays. The paper originally proposes an innovative solution for cooperative traffic surveillance based on vehicular communications capable of: (i) working with low penetration rates of the proposed technology and (ii) of collecting a large set of monitoring data about vehicle mobility in targeted areas of interest. The paper presents insights and lessons learnt from the design and implementation work of the proposed solution. Moreover, it reports extensive performance evaluation results collected on realistic simulation scenarios based on the usage of iTETRIS with real traces of vehicular traffic of the city of Bologna. The reported results show the capability of our proposal to consistently estimate the real vehicular traffic even with low penetration rates of our solution (only 10%).

Driving Behaviour Clustering For Realistic Traffic Micro-Simulators.

Traffic simulators are effective tools to support decisions in urban planning systems, to identify criticalities, to observe emerging behaviours in road networks and to configure road infrastructures, such as road side units and traffic lights. Clearly the more realistic the simulator the more precise the insight provided to decision makers. This paper provides a first step toward the design and calibration of traffic micro-simulator to produce realistic behaviour. The long term idea is to collect and analyse real traffic traces collecting vehicular information, to cluster them in groups representing similar driving behaviours and then to extract from these clusters relevant parameters to tune the microsimulator. In this paper we have run controlled experiments where traffic traces have been synthetized to obtain different driving styles, so that the effectiveness of the clustering algorithm could be checked on known labels. We describe the overall methodology and the results already achieved on the controlled experiment, showing the clusters obtained and reporting guidelines for future experiments.